Preparation And Properties Of Modified Kaolin Reinforced Nylon 6 Flame Retardant Materials

Nylon 6?PA6?is a kind of engineering plastics with excellent mechanical properties,strong oil resistance,good corrosion resistance and high wear resistance.It is one of the preferred base materials for insulating materials of low voltage electrical appliances.However,the defects of PA6 such as poor performance under strong acid or alkaline conditions,easy water absorption and flammability affect the dimensional stability and electrical properties of PA6 products,which greatly limit the application field of PA6.Kaolin can be used as filler to fill reinforced plastics,which can improve the surface properties,dimensional accuracy,mechanical strength,wear resistance,dielectric strength,infrared resistance and chemical corrosion resistance,etc.It has good insulation and mass transfer barrier effect in flame retardant process.In this paper,urea intercalation was prepared by ultrasonic mechanical stirring,and the preparation process was studied by changing the experimental conditions.Adopting ultrasonic method to replace the urea in the kaolin-urea composite intercalation compound to obtain hydrated kaolin by taking the H₂SO₄ solution with different concentrations.The effect of temperature on stripping effect was studied by using low temperature calcination and stripping urea intercalation kaolin and hydrated kaolin.The optimum conditions for the preparation of kaolin/urea composite intercalation compound by ultrasonic,mechanical stirring and urea as intercalation agent were 60?and 80%urea solution at 60?,and the ratio of urea solution was 1g kaolin:2 mL urea solution.The time was 7.5 h,and the intercalation rate reached95.91%.The optimum conditions for preparing hydrous kaolin were 60?,0.5 mol/L H₂SO₄ and 1g of kaolin:10 ml H₂SO₄ solution.the displacement rate is 77.55%;the urea intercalation kaolin is kept for 45min at 200?,and the grain size is smallest;The hydrated kaolin was incubated at 220?for 30 min and the grain size was the smallest.The flame-retardant property,thermal stability and mechanical properties of kaolin/melamine cyanurate?MCA?/PA6 composites were investigated by using modified kaolin and MCA.When 5 parts of urea-intercalated kaolin were peeled,the limiting oxygen index of MCA20 reached 28.0,and the stability of the composites was improved by TG testing.The flame-retardant properties,thermal stability and mechanical properties of kaolin/MCA/melamine polyphosphate?MPP?/PA6 composites were investigated by using modified kaolin,MCA)and melamine polyphosphate?MPP?.The results showed that the addition of MPP did not improve the flame-retardant property,and the kaolin also exhibited no synergistic effect in the flame-retardant system.